My “recent to me” 2001 Cab came with all the factory books and even the original 3 keys but no service records. I did find out after checking with several local dealers that the car had been reasonably serviced. Yet there was nothing on a 40,000 mile and I bought it with 39,000. Off to the local independent shop (recently referred). Set to do the typical 40k plus sparkplugs. When they pulled the plugs, all 6 coil packs were cracked, some larger than others, but each loosing spark. The shop said it’s not uncommon with a 9 year old car, even one with low miles. The owner has been very fair on parts cost and labor. I’ll pick it up tomorrow and am told it will perform much better.

It was much of the recent talk about the benefits of plug changes that got me to do this. Thanks to the other members who so willing share their successes…. And mistakes….

 

I had been warned that cracked coils were common. I just had the 60k service done on my '99 and all 6 were cracked. Even though there were no error codes indicating misfires, I had them all replaced anyways.

 

I'd bet heat is the main cause with them being located on the heads. It wouldn't help if the coils packs are wires wound on paper which would absorb moisture if not used for extended periods. Then I'd be thinking heat expanding moisture would give the plastic a work out if its sealed.

 

Not uncommon at all. Most of the units are cracked or fail the test after only 30-40K miles.
At 60K my service includes them for all cars, because they are failed or failing by that point.

 

I just replaced all mine at 89K miles. It surprised me that I was not getting misfires given how cracked they were. My Bimmer coils held up much better in comparison. They only had white fatigue marks starting to show when I replaced them at 114K miles. Audis are known for their crappy coils...

 

If you dyno the car before and after swapping the coils you can easily note that the coils do make a difference.. Not so much in output as in the smoothness of the dyno plots, bumpy plots usually come from engines with old coils.

 

You can pick these up for $48 a peice from Sunset.
Other than the basic maintence items, these are relatively inexpensive insurance to keep you P-car running right.

Installing them isn't bad either. Far easier than the plugs behind them.
For those looking to chagne out their coils, I have found that a long pair of needle nose pliers with the needle end on a 60 degree angle make the job really easy. That and patience....

 

You can also just seal them all for less than $10.

 

Silicone RTV? or what do you recommend? I haven't seen a cracked coil so I'm uncertain what it needs or how.

Sounds like a reasonable solution to a design/manufacturing flaw.

A coil should last at least 15 years/200k miles

 

My preference is underbody spray. Quick and easy.

 

Is there a Porsche-specified inspect/replace interval for coils?
If not, what is a good rule of thumb in terms of years/miles?

 

Based on an unscientific survey of parts managers, the vast majority of 996's have the orginal coil packs on them with no problems. Just because you hear about numerous failures reported on a forum that specializes in failure reporting, is no reason to conclude it is a major problem. Nor shoud you conclude because a problem appeared to be resoloved by simply replacing all the coil packs, that the problem was, in fact, cracked packs.

You have better odds winning the lottery 2 days in a row than having all 6 packs fail at the same time.

ie. Don't fret about it.

 

I agree.... All 6 packs failing at the same time would be very rare.... I'm sure that mine failed 1 at a time, over the last 9 years ... It was just this point in time the shop looked as they were changing the plugs... Picked it up today ... Runs smoother and better acceleration.... AND.... my 3 spoke steering wheel was installed !!!!! Anyone need 2 Savannah Beige leather wheels with matching airbags cheap? Yes 2... I was stupid before......

 

At least one UK Porsche Boxster site has many reports of coil packs bad. Some of the pictures of the coil packs... One doesn't realize what year 'round driving and salt and grit and whatever on the roads can do to these over time. Owners here in USA of course that drive year round in all kinds of weather face similar issues.

The issue isn't whether all are bad. As you say all 6 going bad at same rare and my unscientific observation is generally the coil packs on the side of the engine that is closest to the outside edge of the road or the curb suffer the most cause they get splashed with more stuff.

The issue is that if 1 or some are bad, replacing these with new ones could result in some imbalance in the coil pack output and performance. The engine might not exhibit any symptoms but peformance could be down a bit. Enough to matter probably not. But one can't say for sure not.

Also, while is replacing one the labor to replace all is not the much. I've never had to replace a coil pack but the 1st one that does bad will trigger a replacement of all. I'm not going to deal with the likelihood of going to the trouble of replacing one only to have another one go out shortly afterwards and have to do the operation a second time. Might as well replace them all.

Then all are new, and there is no possible imbalance from having years old coil packs and brand new ones in service, and one can then just drive the car without having to have the nagging suspicion when the next one will go bad. Also, some of us drive our cars rather long distances and it is not fun to try to schedule any kind of repair while on vacation, especially since most of the time -- it seems -- this vacation takes place around, during a major holiday when every Porsche dealership is closed.

Since most of us get thousands of miles of trouble free driving before coil packs require any attention just replacing them all at first sign of one needing replacing seems the better way to deal with issue.

I'm not a fan of trying to coat or repair a coil pack. The time/effort it takes to get to it one might as well replace the darn thing. Also, the crack may have dust/dirt (possibly electrically conductive) or may even have some moisture trapped. "sealed" the coil pack could deliver substandard performance. It might not trigger a misfire error but the engine may not be running optimally either.

Plus how does this coating affect the temperature at which the coil operates? The coating could cause the coil to run hotter and the material and coil to break down sooner from excessive heat.

Slapping some kind of coating on a cracked coil pack whether the coil pack is bad enough to trigger misfire or just showing its age seems to be on the darker side DIY and shade tree auto repair.

Sincerely,

Macster.

 

The coating does not negatively effect the operation of the coil in any way.